Mobile device trajectory estimation

ABSTRACT

Disclosed is a novel system and method for utilizing information gathered at a based station for tracking a trajectory of a mobile device. Three types of information may be used including radio-layer information, ID information, session based information, or a combination thereof. The information is gathered at cellular base-stations to localize a mobile device. Cell towers have wide penetration and extensive coverage, and base-stations/mobile-devices have access to a lot of information. In one example, a method for tracking mobile device locations at a based station begins with accessing a list of mobile device information previously collected from mobile devices communicatively coupled over the wireless communications network to the base station. Currently active mobile device information measured by the network elements is accessed. A trajectory of the mobile device communicatively coupled to the base station is estimated by mapping the list of information previously collected with the currently active mobile device information.

BACKGROUND

The present invention generally relates to mobile devices, and morespecifically to mobile device location tracking.

Determining the geographic location of mobile devices is an importantproblem, and has applications in a plethora of location-based-services.With the wide and growing adoption of smartphones, there is a rapidlygrowing set of location-based-services designed for use withsmartphones. For example, location information is used in navigationapplications, location-based mobile advertisements and mobile assettracking, to name a few. The primary mechanism by which mobile devicelocation is determined currently is through the use of GlobalPositioning System (GPS) application on the device, which can determinethe device location in an outdoor environment using satellite beacons.The main disadvantage of using GPS for continuous location tracking isthat it drains battery energy quickly. Therefore, a GPS within a mobiledevice cannot be turned on for extended periods of time.

Another method of determining device location is through the use ofdevice connectivity information; for example, based on the WiFi accesspoints that a device can see, its location can be determined relative tothe known locations of those access points. The drawback of this methodis that the deployment of WiFi access points is not centrallycontrolled, their IDs have conflicting and changing names, and they havevery sparse deployment outside urban areas and small coverage areas.

Yet, still another method of continuous tracking is through theinformation of the mobile device's association with base stations. Thebase station ID and the mobile device association are used. Thisprovides only very course grained tracking which may not be sufficientin some applications.

Yet another method of location tracking is by triangulation of mobiledevice's location through the measurement of wireless signals betweenthe mobile device and multiple base stations. This also provides onlycourse grained location estimates which may not be sufficiently precisein some applications.

Further, current location tracking of mobile devices use continuouslocation tracking. This continuous tracking consumes a significantamount of battery power. This continuous drain on battery power isundesirable in mobile device location tracking.

BRIEF SUMMARY

Disclosed is an automated system and method for utilizing informationgathered at a based station for tracking a trajectory of a mobiledevice. Three types of information may be used including radio-layerinformation, ID information, session based information, or a combinationthereof. The information is gathered at cellular base-stations tolocalize a mobile device. Cell towers have wide penetration andextensive coverage, and base-stations/mobile-devices have access to alot of information.

The temporally ordered mobile device measurements are matched withpre-computed spatio-temporal signatures of possible trajectories. Thismatching can be done dynamically by starting with the initial estimatesof the device and obtaining the temporal radio-layer signatures thatcould be generated on different possible trajectories of the device. Foreach match a score is computed which reflects the probability of themobile device being on that trajectory. This score is dynamicallyupdated as more measurements are made. Output the mobile device locationif such a sufficiently high probability or highest score is reached,otherwise declare non-localizable after a certain time-period lapse.

In one example, the method for tracking mobile device locations beginswith accessing a list of mobile device information previously collectedfrom mobile devices communicatively coupled over the wirelesscommunications network to the base station. Currently active mobiledevice information is accessed. The currently active mobile deviceinformation includes timing advance information and/or angle of arrivalinformation. A trajectory of the mobile device communicatively coupledto the base station is estimated by mapping the list of informationpreviously collected with the currently active mobile deviceinformation.

In one example, besides timing advance information, arrival informationor a combination thereof, the mobile device information includesradio-layer information including at least one of channel gain, channelfade fluctuations, received signal strength indicator (RSSI), or acombination thereof.

In another example, besides timing advance information, arrivalinformation or a combination thereof, the mobile device informationincludes identification (ID) information including at least one of amobile device ID, a base station ID, a location area code ID, or acombination thereof.

In yet, another example, besides timing advance information, arrivalinformation or a combination thereof, the mobile device informationincludes session based information including at least one of a mobiledevice ID pair for a voice call, a user-ID pair and server-address for adata session, or a combination thereof.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The accompanying figures wherein reference numerals refer to identicalor functionally similar elements throughout the separate views, andwhich together with the detailed description below are incorporated inand form part of the specification, serve to further illustrate variousembodiments and to explain various principles and advantages all inaccordance with the present invention, in which:

FIG. 1 is a block diagram illustrating one example of an operatingenvironment;

FIG. 2 is a block diagram illustrating a detailed view of a localizationmanager;

FIG. 3 is a table of mobile device information collected at a basestation used by the localization manager of FIG. 2;

FIGS. 4-5 is a flow chart of a mobile device trajectory estimation usingthe information of FIG. 3; and

FIG. 6 is a block diagram illustrating one example of an informationprocessing system.

DETAILED DESCRIPTION

As required, detailed embodiments are disclosed herein; however, it isto be understood that the disclosed embodiments are merely examples andthat the systems and methods described below can be embodied in variousforms. Therefore, specific structural and functional details disclosedherein are not to be interpreted as limiting, but merely as a basis forthe claims and as a representative basis for teaching one skilled in theart to variously employ the present subject matter in virtually anyappropriately detailed structure and function. Further, the terms andphrases used herein are not intended to be limiting, but rather, toprovide an understandable description of the concepts.

The description of the present invention has been presented for purposesof illustration and description, but is not intended to be exhaustive orlimited to the invention in the form disclosed. Many modifications andvariations will be apparent to those of ordinary skill in the artwithout departing from the scope and spirit of the invention. Theembodiment was chosen and described in order to best explain theprinciples of the invention and the practical application, and to enableothers of ordinary skill in the art to understand the invention forvarious embodiments with various modifications as are suited to theparticular use contemplated.

NON-LIMITING DEFINITIONS

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, steps, operations, elements, and/orcomponents, but do not preclude the presence or addition of one or moreother features, integers, steps, operations, elements, components,and/or groups thereof.

The term “angle of arrival” (AoA) measurement is a method fordetermining the direction of propagation of a radio-signal wave incidenton an antenna array. AoA determines the direction typically by measuringthe time difference of arrival at individual elements of the array.

The term “base station” as used herein is typically a fixedreceiver/transmitter that serves as a hub for a wireless network, andmay be the gateway between wired and wireless networks.

The term “identification information” or ID information “mobile deviceidentifier” as used herein is, a base station ID, a location area codeID, a mobile device ID such as telephone number, IMSI number, MSISDN, orother information stored on a SIM card or a combination thereof.

The term “location area code ID” is code associated with a geographicalarea with radio coverage by one or more base stations.

The term “measure by the network element” is information, such as“radio-layer information” that can typically only be available at “basestation” and not available at the mobile device.

The term “mobile device information” is information, typically gatheredat a base station including radio-layer information, ID information, andsession based information used to estimate a trajectory of the device.

The term “network element” as used herein refers to a logical orphysical element within the cellular network that handles the data andcontrol traffic for mobile devices, typically located at a fixedlocation and interconnected with each other through network links.Examples of network elements include base stations, MME, S-GW, P-GW,etc.

The term “radio-layer information” as used here is information on how aradio-signal propagates from the mobile device to the base stationincluding timing advance information, arrival information, channel gain,channel fade fluctuations, received signal strength indicator (RSSI), ora variations or combination thereof.

The term “received signal strength indicator” is often abbreviated(RSSI) and is the relative received radio-signal strength in a wirelessenvironment, in arbitrary units. RSSI is an indication of the powerlevel being received by the antenna. Therefore, the higher the RSSInumber the stronger the signal.

The term “session based information” as used herein is a mobile deviceID pair for a voice call, a user-ID pair and server-address for a datasession, or a combination thereof.

The term “spatio-temporal signatures” as used herein is information“measured by a network element” with both a position information(spatio) and time information (temporal) associated with a given mobiledevice ID (signature).

The term “timing advance” a value that corresponds to a length of time asignal take to reach a base station from a mobile device.

The term “wireless communications network” as used herein includes oneor more communication networks. The wireless communications standard(s)of the network(s) 110 can comprise Code Division Multiple Access (CDMA),Time Division Multiple Access (TDMA), Global System for MobileCommunications (GSM), General Packet Radio Service (GPRS), FrequencyDivision Multiple Access (FDMA), Orthogonal Frequency DivisionMultiplexing (OFDM), Orthogonal Frequency Division Multiple Access(OFDMA), Wireless LAN (WLAN), WiMAX or other IEEE 802.16 standards, LongTerm Evolution (LTE), or any other current or future wirelesscommunication standard. It should be noted that the operatingenvironment 100 can also include a peer-to-peer (P2P) based messagingsystem (not shown) such as a PIN-based messaging system.

Overview

Each geographic location has a radio-layer signature. Even though asingle location of radio-layer information of a mobile device may not beunique, the temporally generated radio-layer information is unique tothe mobile device trajectory over time. Therefore, the combination oflocation-specific radio-layer signatures on a trajectory gives uniquespatio-temporal signature of a trajectory.

A data analytics based approach using information at a base station in awireless communications network is used to determine mobile devicelocalization. The process includes accessing a time-ordered list ofmobile device radio-layer information previously collected from one ormore of mobile devices. This is historic data and can include wirelesschannel gain, received signal strength indicator, base-stationidentifiers, or a combination thereof. Next, active mobile deviceinformation is accessed including timing advance information from atleast one mobile device communicatively coupled to the base station overa wireless communication network. Using the historic and activeinformation, a trajectory of the mobile device communicatively coupledto the base station is estimated by mapping the time-ordered list ofradio-layer information previously collected with the currently activemobile device radio-layer information including timing advanceinformation. Unlike GPS, or WiFi location technologies, the mobiledevice does not need to keep a separate GPS radio or WiFi radio enabledand drain battery power.

The present invention utilizes radio-layer information which is alreadycomputed in the cellular network. This can be easily added usingexisting cellular infrastructure and offered as a service.

Operating Environment

FIG. 1 shows an operating environment 100 according to one embodiment ofthe present invention. The operating environment 100 comprises one ormore wireless communication networks 102 that are communicativelycoupled to one or more wire line networks 104. For purposes ofsimplicity, only the portions of these networks that are relevant toembodiments of the present invention are described. The wire linenetwork 104 acts as a back-end for the wireless communication network102. In this embodiment, the wire line network 104 comprises one or moreaccess/core networks of the wireless communication network 102 and oneor more Internet Protocol (IP) networks such as the Internet. The wireline network 104 communicatively couples, for example, one or morecontent sources/providers, such as a server(s) 106, to the wirelesscommunication network 102. In further embodiments, the back-end is not awire line network. For example, in one embodiment the back-end is awireless network and takes the form of a point-to-point back-end networksuch as a directional microwave network used to transmit and receivesignals bi-directionally. Alternatively, the back-end takes the form ofa network of peers in which a mobile base station (e.g., eNodeB in thecase of LTE) is itself used as a back-end network for other basestations.

The wireless communication network 102 supports any wirelesscommunication standard such as, but not limited to, Global System forMobile Communications (GSM), Code Division Multiple Access (CDMA), TimeDivision Multiple Access (TDMA), General Packet Radio Service (GPRS),Frequency Division Multiple Access (FDMA), Orthogonal Frequency DivisionMultiplexing (OFDM), or the like. The wireless communication network 102includes one or more networks based on such standards. For example, inone embodiment, the wireless communication network 102 comprises one ormore of a Long Term Evolution (LTE) network, an Evolution Data Only(EV-DO) network, a GPRS network, a Universal Mobile TelecommunicationsSystem (UMTS) network, and the like. In the example of FIG. 1, thewireless communication network 102 is an LTE network.

FIG. 1 further shows that one or more mobile devices 108, 110 arecommunicatively coupled to the wireless communication network 102. Themobile devices 108, 110, in this embodiment, are wireless communicationdevices such as two-way radios, cellular telephones, mobile phones,smartphones, two-way pagers, wireless messaging devices, laptopcomputers, tablet computers, desktop computers, personal digitalassistants, and other similar devices. Mobile devices 108, 110 accessthe wireless communication network 102 through one or transceiver nodes112, 114 situated at the edge of the wireless communication network 102.For example, the mobile devices 108, 110 access the wirelesscommunication network 102 through one or more transceiver nodes 112, 114using one or more air interfaces 115 established between the mobiledevices 108, 110 and the transceiver nodes 112, 114.

In another embodiment, one or more mobile devices 108, 110 access thewireless communication network 102 via a wired network and/or anon-cellular wireless network such as, but not limited to, a WirelessFidelity (WiFi) network. For example, the mobile devices 108, 110 can becommunicatively coupled to one or more gateway devices via wired and/orwireless mechanisms that communicatively couples the mobile devices 108,110 to the wireless communications network 102. This gateway device(s),in this embodiment, communicates with the wireless communication network102 via wired and/or wireless communication mechanisms.

The mobile devices 108, 110 interact with the wireless communicationnetwork 102 to send/receive voice and data communications to/from thewireless communication network 104. For example, the mobile devices 108,110 are able to wirelessly request and receive content (e.g., audio,video, text, web pages, etc.) from a provider, such as the server 106,through the wireless communication network 102. The requestedcontent/service is delivered to the wireless communication network 102through the wire line network 104.

A transceiver node 112, 114 is known as a base transceiver station (BTS)or just a base station, a NodeB, and/or an Evolved NodeB (eNodeB)depending on the technology being implemented within the wirelesscommunication network 104. This exemplary embodiment relates to an LTEnetwork, so the illustrated transceiver nodes 112, 114 are eNodeBs. Thetransceiver nodes 112, 114 are communicatively coupled to one or moreantennas communicates directly with the core of the wirelesscommunication network 102. It should be noted that in anotherembodiment, a radio network controller (RNC) or base station controller(BSC) is communicatively coupled to a transceiver node 112, 114 formanaging and controlling one or more base stations.

In the example shown in FIG. 1 one or more mobility management entitiesand serving gateway nodes (MME/S-GW) 116 are communicatively coupled tothe plurality of eNodeBs 112, 114. A packet gateway node (P-GW) 118 iscommunicatively coupled to the MME/S-GW 116 and to the wire line network104 (e.g., Core IP Network). It should be noted that even though FIG. 1shows the MME combined with the S-GW, the MME can be separate anddistinct from the S-GW. It should be noted that the MME/S-GW is alsoreferred to herein as the “MME 116”. The MME/S-GW 116 manages mobility(e.g., a transfer) of the mobile devices across different eNodeBs andalso acts as a serving gateway for data. The P-GW 118 acts as thegateway to the wire line network 104.

In one example, the communication protocols between the mobile devices108, 110 and the P-GW 118 are various 3rd Generation Partnership Project(3GPP) protocols over which the internet protocol (IP) traffic from themobile devices 108, 110 is tunneled. For example, a GPRS tunnelingprotocol (GTP) is utilized between the eNodeBs 112, 114 and the MME/S-GW116 as well as between the MME/S-GW 116 and the P-GW 118. A standardInternet Protocol (IP) is utilized between the P-GW 118 and the wireline network 104. The server(s) 106 has a TCP (Transmission ControlProtocol) socket that communicates with a TCP socket at the mobiledevices 108, 110 when a user wishes to access data from the server 106.An IP tunnel is created from the P-GW 118 to mobile devices 108, 110 foruser traffic and passes through the interim components, such as theMME/S-GW 116.

FIG. 1 further shows that at least one of the eNodeBs 112, 114 and theP-GW 118 are each communicatively coupled to a localization manager 150which provides mobile device trajectory estimation. At least one of thenetwork elements in the cellular network (for example, eNodeBs 112, 114,the MME/S-GW 116, or the P-GW 118) is coupled to a localization manager150. In one embodiment, the localization manager 150 resides within theeNodeB 112. Similarly, in another embodiment, the localization manager150 resides within the P-GW 118 or within MME/S-GW 116. In yet anotherembodiment, the localization manager 150 is separate and distinct fromthe network elements, but is remotely coupled with one or more networkelements.

FIG. 2 is a more detailed example of the localization manager 150. Inparticular, FIG. 2 shows that the localization manager 150 comprisesprevious mobile device information 202, a comparator 204, current activemobile device information 206, and an estimation module 208. FIG. 2further shows that optional active local mobile device information 214is also included within the localization manager 150. This optionalactive local mobile device information 214 is information sent by mobiledevice(s) 108, 110 to the transceiver node 112, 114 (base station). Thisinformation includes global position system (GPS) information, andaccelerometer information. It is important to note that the local mobiledevice information 214 can also be collected historically and storedwith previous mobile device information 202 as an enhancement to thehistory. The localization module 150 and its components are discussed ingreater detail below.

Mobile Device Information

The following is a more detailed discussion on detecting informationfrom mobile devices 108, 110 in the wireless communication network 102.The information is operational information on how wireless signalspropagate from each of the mobile devices 108, 110 back to base stationor transceiver node 112, 114. Referring now to FIG. 3, shown is a table300 of mobile device information collected at a base station used by thelocalization manager 150 of FIG. 2. The first column 302 of the table300 is categories of mobile device information. Shown are fourcategories in each of the rows as follows: radio-layer information 320,identification information 322, session based information 324, andoptional local device information 326. It is important to note that allthe types of information collected 304 in rows 320, 322, 324 are collectfrom the base station or transceiver node 112, 114. Only the optionalinformation in row 326 is collected from the mobile device themselves.Accordingly, other than the optional information, all the information isavailable at the base station or transceiver node 112, 114.

An example of the usage of the categories of mobile information 302 bylocalization manager 150 of FIG. 2 is shown in column 306. For example,in radio-layer information 302 includes one or more of i) timing advanceinformation, ii) arrival information, iii) channel gain, iv) channelfade fluctuations, v) received signal strength indicator (RSSI) or acombination thereof. This radio-layer information 302 may be used fortriangulation of the current mobile location and/or for determining thespeed of the mobile device. Continuing further, the identificationinformation 322 includes one or more of i) base station id, ii) alocation area code ID, and iii) mobile device ID or a combinationthereof. The identification information 322 may be used for determiningthe initial approximate location of the mobile device. Continuing stillfurther, the session based information 324 includes one or more of i)mobile device ID pair for a voice call and/or ii) a user-ID andserver-address pair for a data session, or a combination thereof. Thesession information 324 may be used for simultaneously determining thetrajectories of two active mobile devices. This is useful for answeringqueries about how two users making a call on their respective mobiledevices are moving. Continuing yet still further, the optional localmobile device information 326 includes one or more of: i) GPSinformation from local mobile device, ii) accelerometer Information fromlocal mobile device, WiFi identification, or a combination thereof. Thisis optional local mobile device information 326 may be used forproviding additional information from the device itself including GPScoordinate, accelerometer information, and WiFi information.

Estimating Trajectory of Mobile Device

As mentioned above, mobile device location at a network element isaccomplished using spatio-temporal signatures of mobile deviceinformation, such as radio-layer characteristics, to localize a mobiledevice. Turning now to FIGS. 4-5 are more detailed steps. Shown is aflow chart of mobile device trajectory estimation using the informationfrom table 300 of FIG. 3. The process begins in step 402 and immediatelyproceeds to step 404 where the mobile ID of a mobile device is obtained.The mobile device ID can be a telephone number, an IMSI number, aMSISDN, or other information stored on a SIM card or a combinationthereof. Also a list of mobile device information previously collectedfrom one or more mobile devices coupled over the wireless network to thebase station is accessed. The database (or store of previous mobiledevice information 202) of spatio-temporal mobile device signatures ofvarious trajectories is also periodically updated to account forchanging environment conditions. Using the mobile device ID, a test instep 406 is made to determine if a preliminary estimate of the mobiledevice location using historical information. In response to preliminarylocation estimate being available, historical information may be thelast location recorded for the mobile device ID in step 408. Otherwise,in response to preliminary estimate of mobile device location not beingavailable a uniform estimate is used. The uniform estimate in oneexample is a uniform probability distribution over a certaingeographical area. The uniform probability in a given geographical areacan include the area of the currently known location of the mobiledevice. The location derived from a geographic location associated witha base station, a routing area, a location area a GPS location, a WiFilocation or combination thereof. The process proceeds to step 410.

In step 410, the currently active mobile device information includingradio-layer information measured by a network element for the mobiledevice ID is collected by the localization manager 150. Examples of theinformation collected are shown in table 300 of FIG. 3. This includesradio-layer information, time advance information, angle of arrivalinformation, ID information, session information or a combinationthereof.

At step 412, an estimated trajectory of mobile device ID is calculatedby mapping the time-ordered list of information collected withspatio-temporal signatures. Stated differently, the mobile deviceinformation for the mobile device ID is collected over time. Thisinformation of time-ordered radio-signatures of the mobile device ID isiteratively measured by the network element. These time-orderedradio-signatures are compared with pre-mapped radio-layer signatures ofmobile trajectories in the given geographical area. Trajectories aremapped against different road-network/path/walkway segments within thegeographic area. A determination is made of which one of these segmentsbest fit the data being currently collected. As matches are found,update the probability of the mobile device location. Example methods ofcomparing mobile device information with the pre-mapped mobile devicecould be using dynamic programming, Viterbi algorithm, etc. Thecomparison accounts for the mobile device speed by checking for multiplesampling durations and picking the one that gives the best match. It isimportant to note that radio-layer information, such as timing-advanceand radio-layer information, is location specific and not mobile deviceID specific. A probability of the location of the mobile device IDlocation is updated in step 414. A loop condition is evaluated in step416. An accuracy of the mobile device ID trajectory is compared to agiven threshold. If the accuracy is below the threshold the processcontinues to collect more information back to step 410 to collect moreinformation. A time out interval may also be used in addition to thethreshold condition.

Steps 410, 412, and 414 are repeated until the probability of mobiledevice location in a certain segment is sufficiently high as comparedwith the threshold. The threshold and timeout can be a pre-determinedthreshold and timeout set by a user, by the system or dynamically basedon historical data, or a combination thereof. Otherwise, the processcontinues to step 418 in which the mobile device trajectory is renderedor furnished and the process ends at step 420.

It should be appreciated that the flow diagrams hereof are illustrative.One or more of the operative steps illustrated in any of the flowdiagrams may be performed in a differing order. Other operations, forexample, may be added, modified, enhanced, condensed, integrated, orconsolidated with the steps thereof. Such variations are intended tofall within the scope of the appended claims. All or portions of theflow diagrams may be implemented partially or fully in hardware inconjunction with machine executable instructions.

Information Processing System

Referring now to FIG. 6, this figure is a block diagram illustrating aninformation processing system that can be utilized in embodiments of thepresent invention. The information processing system 602 is based upon asuitably configured processing system configured to implement one ormore embodiments of the present invention (e.g., the NE 154 of FIG. 1).Any suitably configured processing system can be used as the informationprocessing system 602 in embodiments of the present invention. Thecomponents of the information processing system 602 can include, but arenot limited to, one or more processors or processing units 604, a systemmemory 606, and a bus 608 that couples various system componentsincluding the system memory 606 to the processor 604.

The bus 608 represents one or more of any of several types of busstructures, including a memory bus or memory controller, a peripheralbus, an accelerated graphics port, and a processor or local bus usingany of a variety of bus architectures. By way of example, and notlimitation, such architectures include Industry Standard Architecture(ISA) bus, Micro Channel Architecture (MCA) bus, Enhanced ISA (EISA)bus, Video Electronics Standards Association (VESA) local bus, andPeripheral Component Interconnects (PCI) bus.

Although not shown in FIG. 6, the main memory 606 includes thelocalization manager 150. The localization manager 150 can reside withinthe processor 604, or be a separate hardware component. The systemmemory 606 can also include computer system readable media in the formof volatile memory, such as random access memory (RAM) 610 and/or cachememory 612. The information processing system 602 can further includeother removable/non-removable, volatile/non-volatile computer systemstorage media. By way of example only, a storage system 614 can beprovided for reading from and writing to a non-removable or removable,non-volatile media such as one or more solid state disks and/or magneticmedia (typically called a “hard drive”). A magnetic disk drive forreading from and writing to a removable, non-volatile magnetic disk(e.g., a “floppy disk”), and an optical disk drive for reading from orwriting to a removable, non-volatile optical disk such as a CD-ROM,DVD-ROM or other optical media can be provided. In such instances, eachcan be connected to the bus 608 by one or more data media interfaces.The memory 606 can include at least one program product having a set ofprogram modules that are configured to carry out the functions of anembodiment of the present invention.

Program/utility 616, having a set of program modules 618, may be storedin memory 606 by way of example, and not limitation, as well as anoperating system, one or more application programs, other programmodules, and program data. Each of the operating system, one or moreapplication programs, other program modules, and program data or somecombination thereof, may include an implementation of a networkingenvironment. Program modules 618 generally carry out the functionsand/or methodologies of embodiments of the present invention.

The information processing system 602 can also communicate with one ormore external devices 620 such as a keyboard, a pointing device, adisplay 622, etc.; one or more devices that enable a user to interactwith the information processing system 602; and/or any devices (e.g.,network card, modem, etc.) that enable computer system/server 602 tocommunicate with one or more other computing devices. Such communicationcan occur via I/O interfaces 624. Still yet, the information processingsystem 602 can communicate with one or more networks such as a localarea network (LAN), a general wide area network (WAN), and/or a publicnetwork (e.g., the Internet) via network adapter 626. As depicted, thenetwork adapter 626 communicates with the other components ofinformation processing system 602 via the bus 608. Other hardware and/orsoftware components can also be used in conjunction with the informationprocessing system 602. Examples include, but are not limited to:microcode, device drivers, redundant processing units, external diskdrive arrays, RAID systems, tape drives, and data archival storagesystems.

Non-Limiting Examples

As will be appreciated by one skilled in the art, aspects of the presentinvention may be embodied as a system, method, or computer programproduct. Accordingly, aspects of the present invention may take the formof an entirely hardware embodiment, an entirely software embodiment(including firmware, resident software, micro-code, etc.) or anembodiment combining software and hardware aspects that may allgenerally be referred to herein as a “circuit,” “module” or “system.”Furthermore, aspects of the present invention may take the form of acomputer program product embodied in one or more computer readablemedium(s) having computer readable program code embodied thereon.

Any combination of one or more computer readable medium(s) may beutilized. The computer readable medium may be a computer readable signalmedium or a computer readable storage medium. A computer readablestorage medium may be, for example, but not limited to, an electronic,magnetic, optical, electromagnetic, infrared, or semiconductor system,apparatus, or device, or any suitable combination of the foregoing. Morespecific examples (a non-exhaustive list) of the computer readablestorage medium would include the following: an electrical connectionhaving one or more wires, a portable computer diskette, a hard disk, arandom access memory (RAM), a read-only memory (ROM), an erasableprogrammable read-only memory (EPROM or Flash memory), an optical fiber,a portable compact disc read-only memory (CD-ROM), an optical storagedevice, a magnetic storage device, or any suitable combination of theforegoing. In the context of this document, a computer readable storagemedium may be any tangible medium that can contain, or store a programfor use by or in connection with an instruction execution system,apparatus, or device.

A computer readable signal medium may include a propagated data signalwith computer readable program code embodied therein, for example, inbaseband or as part of a carrier wave. Such a propagated signal may takeany of a variety of forms, including, but not limited to,electro-magnetic, optical, or any suitable combination thereof. Acomputer readable signal medium may be any computer readable medium thatis not a computer readable storage medium and that can communicate,propagate, or transport a program for use by or in connection with aninstruction execution system, apparatus, or device.

Program code embodied on a computer readable medium may be transmittedusing any appropriate medium, including but not limited to wireless,wireline, optical fiber cable, RF, etc., or any suitable combination ofthe foregoing.

Computer program code for carrying out operations for aspects of thepresent invention may be written in any combination of one or moreprogramming languages, including an object oriented programming languagesuch as Java, Smalltalk, C++ or the like and conventional proceduralprogramming languages, such as the “C” programming language or similarprogramming languages. The program code may execute entirely on theuser's computer, partly on the user's computer, as a stand-alonesoftware package, partly on the user's computer and partly on a remotecomputer or entirely on the remote computer or server. In the latterscenario, the remote computer may be connected to the user's computerthrough any type of network, including a local area network (LAN) or awide area network (WAN), or the connection may be made to an externalcomputer (for example, through the Internet using an Internet ServiceProvider).

Aspects of the present invention have been discussed above withreference to flowchart illustrations and/or block diagrams of methods,apparatus (systems) and computer program products according to variousembodiments of the invention. It will be understood that each block ofthe flowchart illustrations and/or block diagrams, and combinations ofblocks in the flowchart illustrations and/or block diagrams, can beimplemented by computer program instructions. These computer programinstructions may be provided to a processor of a general purposecomputer, special purpose computer, or other programmable dataprocessing apparatus to produce a machine, such that the instructions,which execute via the processor of the computer or other programmabledata processing apparatus, create means for implementing thefunctions/acts specified in the flowchart and/or block diagram block orblocks.

These computer program instructions may also be stored in a computerreadable medium that can direct a computer, other programmable dataprocessing apparatus, or other devices to function in a particularmanner, such that the instructions stored in the computer readablemedium produce an article of manufacture including instructions whichimplement the function/act specified in the flowchart and/or blockdiagram block or blocks.

The computer program instructions may also be loaded onto a computer,other programmable data processing apparatus, or other devices to causea series of operational steps to be performed on the computer, otherprogrammable apparatus or other devices to produce a computerimplemented process such that the instructions which execute on thecomputer or other programmable apparatus provide processes forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks.

The description of the present application has been presented forpurposes of illustration and description, but is not intended to beexhaustive or limited to the invention in the form disclosed. Manymodifications and variations will be apparent to those of ordinary skillin the art without departing from the scope and spirit of the invention.The embodiment was chosen and described in order to best explain theprinciples of the invention and the practical application, and to enableothers of ordinary skill in the art to understand the invention forvarious embodiments with various modifications as are suited to theparticular use contemplated.

What is claimed is:
 1. A method for tracking mobile device locations,the method at network element in a wireless communications networkcomprising: accessing a list of mobile device information previouslycollected from one or more of mobile devices communicatively coupledover the wireless communications network to a base station; accessingcurrently active mobile device information measured by the networkelement; and estimating a trajectory of the mobile devicecommunicatively coupled to a base station by mapping the list ofinformation previously collected with the currently active mobile deviceinformation, wherein the mobile device information measured by thenetwork element is radio-layer information includes timing advanceinformation that corresponds to a length of time a radio-signal takes toreach a based station from at least one mobile device coupled over thewireless communications network.
 2. The method of claim 1, wherein theradio-layer information including at least one of channel gain; channelfade fluctuations; or a combination thereof.
 3. The method of claim 1,wherein the mobile device information includes identification (ID)information including at least one of a mobile device ID, a base stationID, a location area code ID, or a combination thereof.
 4. The method ofclaim 1, wherein the mobile device information includes session basedinformation including at least one of a mobile device ID pair for avoice call, a user-ID pair and server-address for a data session, or acombination thereof.
 5. The method of claim 1, wherein the accessingcurrently active mobile device information includes accessinginformation for at least one mobile device with a mobile deviceidentifier (ID) and a mobile device with a same mobile device identifier(ID) that has been previously collected.
 6. The method of claim 5,wherein the estimating the trajectory of the mobile devicecommunicatively coupled to the base station by mapping the list ofinformation previously collected with the currently active mobile deviceinformation further includes using a previously estimated location forthe active mobile device as a starting point for the trajectory.
 7. Themethod of claim 1, wherein the accessing a list of mobile deviceinformation previously collected from one or more of mobile devicesincludes a time-order list of mobile device information.
 8. The methodof claim 7, wherein the time-order list of mobile device information iscollected over non-uniform time intervals.
 9. The method of claim 1,wherein the currently active mobile device information is pre-computedusing historical information.
 10. The method of claim 9, wherein thecurrently active mobile device information is pre-computed over time.11. The method of claim 1, further comprising: receiving local mobiledevice information from at least one of the mobile devices, the localdevice information including at least one of global positioning system(GPS) information, and accelerometer information; and storing this localdevice information in the list of mobile device information previouslycollected.
 12. The method of claim 1, further comprising: receivinglocal mobile device information from the mobile device, the local deviceinformation including at least one of global positioning system (GPS)information, and accelerometer information and using this local deviceinformation for estimating the trajectory.
 13. The method of claim 1,wherein the trajectory of the mobile device is estimated dynamically bymatching the list of mobile device information of the mobile device witha list of pre-computed signatures for possible locations and maintaininga score of a match.
 14. The method of claim 12, wherein the trajectorywith a highest score and whose score is above a pre-determined thresholdis selected as the estimate of the trajectory.